The Astrobiology Primer 2.o, co-authored by PI Sara Walker, is an educational document reviewing the diversity of astrobiology research published in the journal Astrobiology! This is a follow-up on the highly successful Astrobiology Primer 1.0 project published 10 years ago. The 2.0 version is open-access and is available here.

Emergence@ASU PI Sara Walker and collaborator Chiara Marletto have been awarded a grant to study the "Physics of the Observer" from the Foundational Questions in Science Institute! Their project titled "Accommodating observers in fundamental physics with causal mechanics" will examine how to reconcile information with causal power, as necessary for observers to be active participants in the unfolding of the universe, and local, reversible laws as characterize our universe. Read the full project description here.

Emergence@ASU graduate students Harrison Smith and Tessa Fisher are attending a NASA-sponsored "workshop without walls" as part of the NASA Nexus for Exoplanet System Science (NExSS). The workshop isaimed at setting future directions in exoplanet biosignatures and has been profiled in Nature, and Scientific American. Emergence@ASU PI Sara Walker will deliver a plenary talk on "Statistical Signatures of Life" as part of the workshop. The full workshop agenda is available here and is open for remote participation!

One of the most remarkable features of the > 3.5 billion year history of life on Earth is the apparent trend of innovation and open-ended growth of complexity. Similar trends are apparent in artificial and technological systems. However, a general framework for understanding open-ended evolution as it might occur in biological or technological systems has not yet been achieved. Here, we cast the problem within the broader context of dynamical systems theory to uncover and characterize mechanisms for producing open-ended evolution (OEE). We present formal definitions of two hallmark features of OEE: unbounded evolution and innovation. We define unbounded evolution as patterns that are non-repeating within the expected Poincare\'e recurrence time of an equivalent isolated system, and innovation as trajectories not observed in isolated systems. As a case study, we test three new variants of cellular automata (CA) that implement time-dependent update rules against these two definitions. We find that each is capable of generating conditions for OEE, but vary in their ability to do so. Our results demonstrate that state-dependent dynamics, widely regarded as a hallmark feature of life, statistically out-perform other candidate mechanisms. It is also the only mechanism to produce OEE in a scalable manner, consistent with notions of OEE as ongoing production of complexity. Our results thereby suggest a new framework for unifying the mechanisms for generating OEE with features distinctive to life and its artifacts, with wide applicability to both biological and artificial systems.

A preprint of an essay by Sara Walker and Paul Davies, titled "The "Hard Problem" of Life" is now available on the arxiv preprint server. The essay is part of a collection to appear in a book titled "From Matter to Life: Information and Causality" published by Cambridge University Press and edited by Sara Walker, Paul Davies and George Ellis, due to appear later this year.

Chalmer's famously identified pinpointing an explanation for our subjective experience as the "hard problem of consciousness". He argued that subjective experience constitutes a "hard problem" in the sense that its explanation will ultimately require new physical laws or principles. Here, we propose a corresponding "hard problem of life" as the problem of how `information' can affect the world. In this essay we motivate both why the problem of information as a causal agent is central to explaining life, and why it is hard - that is, why we suspect that a full resolution of the hard problem of life will, similar to as has been proposed for the hard problem of consciousness, ultimately not be reducible to known physical principles.Read more here.

A new perspective by Sara Walker and Leroy Cronin titled "Beyond Prebiotic Chemistry" is available in this week's issue of Science. The perspective explores the dynamic properties of networks that might be necessary for the emergence of the living state, and proposes that uncovering ``laws of life'' might be necessary to solving its origins. The full text is available from Science.

Postdoctoral scholar Hyunju Kim heads to Korea to give a talk on "Multilevel evolution of chemical reaction networks" at the NetSci2016 meeting held in Soeul 5/30 - 6/3. The full program may be found here.